As a method for transdermal administration of a drug, application of a solution or ointment to the skin surface and a transdermal preparation in the form of a patch have conventionally been used. At present, however, in an attempt to increase the skin permeability of a drug, it has been tried to topically destroy the stratum corneum with small needles (microneedles or micropins) to forcedly deliver the drug to the dermal layer.
As the material of a microneedle used to puncture the skin, metals, various resins and the like are used. To suppress disorders of the skin, biodegradable materials tend to be used often. However, when the material of the microneedle is a biodegradable resin and the angle of puncture relative to the skin is a little off perpendicular, the small needles of the microneedle break or bend easily, making it difficult to appropriately puncture the skin (patent document 1).
Thus, various applicators (insertion tools) used to perpendicularly puncture the skin with a microneedle have been developed (patent document 2). Recently, those enabling easy and simple puncture of the skin by simply pressing with finger(s) have been developed (patent documents 3, 4).
However, when a microneedle patch that can be fixed by adhesion to the skin with a tape was produced and actually used, adhesion to the skin was clarified to be insufficient during removal of the assisting tool of the patch since the microneedle is lifted up or separated from the skin.
It has also been clarified that transfer of a tape adhered to the applicator with an adhesive onto the skin sometimes fails. To solve this, an adhesive having a weak adhesion power may be used between the applicator and the tape; however, a dilemma ultimately occurs in that it cannot stand distribution and the like.
Furthermore, certain insertion of needles into the skin was sometimes unavailable. Whether or not needles can be inserted into the skin is considered to depend on whether the stress of the microneedle to the skin exceeds a certain level. However, the conventional method of simply pressing with finger(s) problematically cannot determine the stress.
As mentioned above, it is further necessary to study a holding tool and a tape for a microneedle patch to form a microneedle patch and afford a practical product.